Using my faucet, it takes 6 minutes to fill our water tank. Using my neighbor's hose, it takes 9 minutes. How long would it take if i used both the faucet and the hose?

Answer 1

3 minutes 36 seconds. but i don't know why

Answer 2

1/6 + 1/9 = x
3/18 + 2/18 = x
x = 5/18 * 1
x = 18/5
x = 3.6 minutes

Answer 3

use this formula
t/a+t/a=1
where t=together and a=alone
x/6 + x/9 = 1
(6x+9x)/54 =1
15x=54
x=54/15
x=3 3/5 minutes = 3minutes 36 seconds